Elucidation of effect and mechanism of solar activity on the Arctic Oscillation

2017 Fiscal Year Final Research Report

• Project/Area Number: 26281016
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: Japan, Meteorological Research Institute
• Principal Investigator: Kuroda Yuhji 気象庁気象研究所, 気候研究部, 研究官 (80343888)
• Co-Investigator(Kenkyū-buntansha): 小寺 邦彦 名古屋大学, 宇宙地球環境研究所, 招へい教員 (70343887) ; 吉田 康平 気象庁気象研究所, 気候研究部, 研究官 (10636038) ; 柴田 清孝 高知工科大学, 環境理工学群, 教授 (50354494) ; 出牛 真 気象庁気象研究所, 環境・応用気象研究部, 主任研究官 (00354499)
• Research Collaborator: DEUSHI MAKOTO 気象庁, 地球環境海洋部, 環境気象管理官付 ; MUKOUGAWA HITOSHI 京都大学, 防災研究所, 教授 ; Matthes Katja ヘルムホルツ海洋研究所, 教授 ; Gray Lesley オックスフォード大学, 教授
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 太陽活動 / 北大西洋振動 / 成層圏対流圏結合 / 海洋変動 / 気候変動

Outline of Final Research Achievements

The influence of the solar cycle on the North Atlantic Oscillation (NAO) from the upper stratosphere to the surface was examined through lagged regression analyses using recent observations, historical observations, and an earth system model simulation. The propagation of the solar signal was well explained by a top-down mechanism modulated by the ocean: The solar signal first appears in the subtropical upper stratosphere as a temperature signal, the associated zonal wind signal propagates downward to the surface through the activity of the Polar-night Jet Oscillation, and finally the NAO is driven at the surface around the solar activity peak years. This signal is further modulated in such a way that the positive NAO signal tends to appear earlier in the winter as the number of years after the solar activity peak increases. The solar-NAO relationship on a 50-year time scale also suggest that nonlinear interactions occur between solar forcing and ocean dynamics.

Free Research Field

気候変動